Directional Moiré Boosting Using Spatial Filtering

Overlapping of two or more grating structures of small frequency differences gives rise to the Moiré patterns. While the overall moiré patterns are widely studied, in many cases – specially in case of a zonal fringe analysis – zone or direction based highlighting or suppression of moiré patterns are very helpful. This paper presents a simple method for directional boosting of moiré patterns, generated using Spatial Light Modulator (SLM) based interferometric setup, using the spatial filtering technique. Keywords: Moiré, Spatial Filter, Directional Boosting, Interferometry, Spatial Light Modulator, Optics

The Direction of Arrival Location Deception Model Counter Duel Baseline Phase Interferometer Based on Frequency Diverse Array

With the emergence and development of the passive localization, the radiation source is more visible for the location system which endangers their survival. Therefore, there is an urgent demand for the radio frequency (RF) stealth technology. An effective method to realize RF stealth is location deception, therefore, for the passive localization system, this paper proposes a direction of arrival (DOA) location deception method using the frequency diverse array (FDA) against the dual baseline phase interferometer. Since the direction-finding of the dual baseline phase interferometer is based on the received signal with fixed frequency, the FDA signal has a deception effect on the interferometer owing to the introduction of the small frequency increment. Considering the influence of the frequency increment sequence on the deception effect, we derive the optimizations of the DOA location deception via the average location deviation for the sampling time in the case of no noise and noise, respectively. Besides, considering the time dependency of the beam, we investigate the average SNR (ASNR) and the corresponding CRLB to verify the proposed method. Numerical examples and simulations show that the proposed method can counter the interferometer by realizing location deception.

Square Patch Antenna for Mobile Applications

This paper presents the result for different standard thickness values, and the result is performed by circularly polarized, Square patch antenna with a small frequency-ratio is proposed for mobile applications. The antenna has become a necessity for many applications in recent wireless communications such as Radar, Microwave and space communication. The proposed antenna design on different shapes and analyzed result in resonant frequency will be 8.2GHz. A single micro-strip feed-line is underneath the centre of the coupling aperture ground-plane. The frequency-ratio of the antenna can be controlled by adjusting the slot arm lengths. At 12GHz frequency and the tested result on IE3D SIMULATOR parameters are for X-axis -21.6mm to 21.6mm, Y-axis -21.6mm to 21.6. After that results are verified and simulated, S-Parameter = -25.34dB, Field Gain = 9.463dB, Directivity = 10.57dB, Efficiency for Antenna = 77.75% and VSWR = 0.97. All results shown are simulated.

Production of good quality holograms by the THz pulsed vortex beams

In this paper, we discuss the quality of holograms based on the calculation of the modulation depth. It’s shown that the terahertz (THz) pulsed vortex beams play a vital role in holography filed, where two lasers with frequency difference have used. The THz vortex beams give new regions of larger frequency detuning and an important value of the modulation depth and fringe contrast (MDFC ratio) for obtaining the best holograms contrary to the Gaussian beams for which the best holograms are realized for small frequency detuning. The particular cases such as, Gaussian beam and single cycle pulses are deduced from our result. Numerical simulations are also presented to study the dependence of the MDFC ratio on the frequency detuning for THz vortex beams and Gaussian beams. This research could be beneficial in holographic interferometry, and it will firmly establish as a tool for scientific and engineering studies.

The Numerical Solutions of Nonlinear Time-Fractional Differential Equations by LMADM

This paper presents a numerical scheme for solving nonlinear time-fractional differential equations in the sense of Caputo. This method relies on the Laplace transform together with the modified Adomian method (LMADM), compared with the Laplace transform combined with the standard Adomian Method (LADM). Furthermore, for the comparison purpose, we applied LMADM and LADM for solving nonlinear time-fractional differential equations to identify the differences and similarities. Finally, we provided two examples regarding the nonlinear time-fractional differential equations, which showed that the convergence of the current scheme results in high accuracy and small frequency to solve this type of equations.